Another mama checking in here, my addicted son has been in and out of recovery/relapse for about 15 years (gasp, I can't believe it's been that long) and I learned that nothing I said or did could change what he did. I gave my whole life trying to save him and almost died myself in the process.
As others have said, there are worse places than jail for your son. Sometimes God's gifts come strangely wrapped, and jail just might save his life.
Please call the police and get a restraining order to keep him away from your house before someone gets hurt.
My prayers go out for all of you.
Hugs